We show that a (square-root 3 x square-root 3) buckling distortion with one raised and two lowered surface atoms per unit cell lowers by as much as 0.18 eV/(surface atom) the energy of the clean, unreconstructed Si(111) surface. On the defect-free surface this state is not a true energy minimum, and is unstable against conversion into the lower energy (2 x 1) pi-bonded chain reconstruction. A low concentration of added surface vacancies, however, is found to yield a buckled (square-root 3 x square-root 3) state which is a stable local minimum. Predictions are made for possible scanning-tunneling-microscopy observation of this displacive reconstruction.
THEORY OF VACANCY-STABILIZED (SQUARE-ROOT-3 X SQUARE-ROOT-3) DISPLACIVE RECONSTRUCTION OF THE CLEAN SI(111) SURFACE
ANCILOTTO, FRANCESCO;
1991
Abstract
We show that a (square-root 3 x square-root 3) buckling distortion with one raised and two lowered surface atoms per unit cell lowers by as much as 0.18 eV/(surface atom) the energy of the clean, unreconstructed Si(111) surface. On the defect-free surface this state is not a true energy minimum, and is unstable against conversion into the lower energy (2 x 1) pi-bonded chain reconstruction. A low concentration of added surface vacancies, however, is found to yield a buckled (square-root 3 x square-root 3) state which is a stable local minimum. Predictions are made for possible scanning-tunneling-microscopy observation of this displacive reconstruction.Pubblicazioni consigliate
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